diff --git a/src/ConfigInspectorManager.php b/src/ConfigInspectorManager.php
index 8104bbd..e2165fa 100644
--- a/src/ConfigInspectorManager.php
+++ b/src/ConfigInspectorManager.php
@@ -196,7 +196,7 @@ class ConfigInspectorManager {
    *   The corresponding validatability.
    */
   protected function computeTreeValidatability(TraversableTypedDataInterface $tree) : ConfigSchemaValidatability {
-    $defining_config_schema_type = $tree->getDataDefinition()->getDataType();
+    $defining_config_schema_type = self::getDataType($tree);
 
     // "sequence" or "mapping" are not acceptable defining config schema types;
     // that just means that a generic container is used. Go up the tree until a
@@ -204,7 +204,7 @@ class ConfigInspectorManager {
     $node = $tree;
     while (in_array($defining_config_schema_type, ['mapping', 'sequence'], TRUE)) {
       $node = $node->getParent();
-      $defining_config_schema_type = $node->getDataDefinition()->getDataType();
+      $defining_config_schema_type = self::getDataType($node);
     }
 
     $validatability = new ConfigSchemaValidatability($tree->getPropertyPath(), $this->getNodeConstraints($tree), $defining_config_schema_type);